draft-ietf-pim-group-rp-mapping-01.txt   draft-ietf-pim-group-rp-mapping-02.txt 
PIM Working Group B. Joshi PIM Working Group B. Joshi
Internet-Draft Infosys Technologies Ltd. Internet-Draft Infosys Technologies Ltd.
Expires: December 27, 2009 A. Kessler Expires: March 26, 2010 A. Kessler
Cisco Systems, Inc. Cisco Systems, Inc.
D. McWalter D. McWalter
Data Connection Ltd Data Connection Ltd
June 25, 2009 September 22, 2009
PIM Group-to-RP Mapping PIM Group-to-RP Mapping
draft-ietf-pim-group-rp-mapping-01.txt draft-ietf-pim-group-rp-mapping-02.txt
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
skipping to change at page 1, line 35 skipping to change at page 1, line 35
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on December 27, 2009. This Internet-Draft will expire on March 26, 2010.
Copyright Notice Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the Copyright (c) 2009 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents in effect on the date of Provisions Relating to IETF Documents in effect on the date of
publication of this document (http://trustee.ietf.org/license-info). publication of this document (http://trustee.ietf.org/license-info).
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
skipping to change at page 3, line 15 skipping to change at page 3, line 15
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Existing algorithm . . . . . . . . . . . . . . . . . . . . . . 6 3. Existing algorithm . . . . . . . . . . . . . . . . . . . . . . 6
4. Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . 7 4. Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . 7
5. Common use cases . . . . . . . . . . . . . . . . . . . . . . . 8 5. Common use cases . . . . . . . . . . . . . . . . . . . . . . . 8
6. Proposed algorithm . . . . . . . . . . . . . . . . . . . . . . 10 6. Proposed algorithm . . . . . . . . . . . . . . . . . . . . . . 10
7. Deprecation of MIB Objects . . . . . . . . . . . . . . . . . . 12 7. Deprecation of MIB Objects . . . . . . . . . . . . . . . . . . 12
8. Clarification for MIB Objects . . . . . . . . . . . . . . . . 13 8. Clarification for MIB Objects . . . . . . . . . . . . . . . . 13
9. Migration to the new algorithm . . . . . . . . . . . . . . . . 14 9. Use of dynamic group-to-rp mapping protocols . . . . . . . . . 14
10. Security Consideration . . . . . . . . . . . . . . . . . . . . 15 10. Security Consideration . . . . . . . . . . . . . . . . . . . . 15
11. IANA Consideration . . . . . . . . . . . . . . . . . . . . . . 16 11. IANA Consideration . . . . . . . . . . . . . . . . . . . . . . 16
12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 17 12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 17
13. Normative References . . . . . . . . . . . . . . . . . . . . . 18 13. Normative References . . . . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
1. Introduction 1. Introduction
Multiple mechanisms exist today to create and distribute Group-to-RP Multiple mechanisms exist today to create and distribute Group-to-RP
mappings. Each PIM-SM router may learn Group-to-RP mappings through mappings. Each PIM-SM router may learn Group-to-RP mappings through
skipping to change at page 10, line 10 skipping to change at page 10, line 10
o More use cases o More use cases
By no means, the above list is complete. Please drop a mail to By no means, the above list is complete. Please drop a mail to
'authors' if you see any other use case for this. 'authors' if you see any other use case for this.
6. Proposed algorithm 6. Proposed algorithm
We propose following algorithm here which addresses the above We propose following algorithm here which addresses the above
mentioned shortcomings in the existing mechanism: mentioned shortcomings in the existing mechanism:
1. If the Multicast Group Address being looked up contains an 1. If the Multicast Group Address being looked up contains an
embedded RP, RP address extracted from the Group address is embedded RP, RP address extracted from the Group address is
selected as Group-to-RP mapping. selected as Group-to-RP mapping.
2. If the Multicast Group Address being looked up is in the SSM 2. If the Multicast Group Address being looked up is in the SSM
range or is configured for Dense mode, no Group-to-RP mapping is range or is configured for Dense mode, no Group-to-RP mapping is
selected, and this algorithm terminates. Alternatively, a RP selected, and this algorithm terminates. Alternatively, a RP
with address type 'unknown' can be selected. Please look at with address type 'unknown' can be selected. Please look at
section #8 for more details on this. section #8 for more details on this.
3. From the set of all Group-to-RP mapping entries, the subset whose 3. From the set of all Group-to-RP mapping entries, the subset
group prefix contains the multicast group that is being looked whose group prefix contains the multicast group that is being
up, are selected. looked up, are selected.
4. If there are no entries available, then the Group-to-RP mapping 4. If there are no entries available, then the Group-to-RP mapping
is undefined. is undefined.
5. If there are multiple entries available, a subset of those Group- 5. If there are multiple entries available, a subset of those
to-RP mapping is selected that are learned using 'static' Group-to-RP mapping is selected that are learned using 'static'
configuration and are configured with 'override-dynamic' flag. configuration and are configured with 'override-dynamic' flag.
* If there is only one entry available then that is selected as * If there is only one entry available then that is selected as
Group-to-RP mapping. Group-to-RP mapping.
* If there are multiple entries available, we continue with the * If there are multiple entries available, we continue with the
algorithm with this smaller set of Group-to-RP Mappings algorithm with this smaller set of Group-to-RP Mappings
* If there are no static entries with 'override-dynamic' flag * If there are no static entries with 'override-dynamic' flag
set then we continue with the original subset of Group-to-RP set then we continue with the original subset of Group-to-RP
Mappings from step 2. Mappings from step 2.
6. A longest prefix match is performed on the subset of Group-to-RP 6. A longest prefix match is performed on the subset of Group-to-RP
Mappings. Mappings.
* If there is only one entry available then that is selected as * If there is only one entry available then that is selected as
Group-to-RP mapping. Group-to-RP mapping.
* If there are multiple entries available, we continue with the * If there are multiple entries available, we continue with the
algorithm with this smaller set of Group-to-RP Mappings algorithm with this smaller set of Group-to-RP Mappings
7. From the remaining set of Group-to-RP Mappings we select the 7. From the remaining set of Group-to-RP Mappings we select the
subset of entries based on the preference for the PIM modes which subset of entries based on the preference for the PIM modes
they are assigned. A Group-to-RP mapping entry with PIM Mode which they are assigned. A Group-to-RP mapping entry with PIM
'BIDIR' will be preferred to an entry with PIM Mode 'PIM-SM' Mode 'BIDIR' will be preferred to an entry with PIM Mode
'PIM-SM'
* If there is only one entry available then that is selected as * If there is only one entry available then that is selected as
Group-to-RP mapping. Group-to-RP mapping.
* If there are multiple entries available, we continue with the * If there are multiple entries available, we continue with the
algorithm with this smaller set of Group-to-RP Mappings algorithm with this smaller set of Group-to-RP Mappings
8. From the remaining set of Group-to-RP Mappings we select the 8. From the remaining set of Group-to-RP Mappings we select the
subset of the entries based on the origin. Origin preference subset of the entries based on the origin. Origin preference
will be 'bsr', 'auto-rp', 'static' and 'other'. will be 'bsr', 'auto-rp', 'static' and 'other'.
* If there is only one entry available then that is selected as * If there is only one entry available then that is selected as
Group-to-RP mapping. Group-to-RP mapping.
* If there are multiple entries available, we continue with the * If there are multiple entries available, we continue with the
algorithm with this smaller set of Group-to-RP Mappings algorithm with this smaller set of Group-to-RP Mappings
9. From the remaining set of Group-to-RP Mappings we will select the 9. If the remaining Group-to-RP mappings were learned through BSR
RP with the highest IP address. This will serve as a final and the PIM Mode of the Group is 'PIM-SM' then the hash function
tiebreaker. will be used to choose the RP. The RP with the highest
resulting hash value will be selected.
* If more than one RP has the same highest hash value we
continue with the algorithm with those Group-to-RP mappings.
* If the remaining Group-to-RP mappings were NOT learned from
BSR we continue the algorithm with the next step
10. From the remaining set of Group-to-RP Mappings we will select
the RP with the highest IP address. This will serve as a final
tiebreaker.
7. Deprecation of MIB Objects 7. Deprecation of MIB Objects
Group-to-RP mapping algorithm defined in PIM-STD-MIB [RFC5060] does Group-to-RP mapping algorithm defined in PIM-STD-MIB [RFC5060] does
not specify the usage of 'pimGroupMappingPrecedence' and not specify the usage of 'pimGroupMappingPrecedence' and
'pimStaticRPPrecedence' objects in 'pimGroupMappingTable' table 'pimStaticRPPrecedence' objects in 'pimGroupMappingTable' table
clearly. With the newly proposed algorithm in this document, these clearly. With the newly proposed algorithm in this document, these
MIB objects would not be required. So we propose to deprecate these MIB objects would not be required. So we propose to deprecate these
MIB objects from PIM-STD-MIB. Also the newly proposed algorithm in MIB objects from PIM-STD-MIB. Also the newly proposed algorithm in
this document MUST be preferred over Group-to-RP mapping algorithm this document MUST be preferred over Group-to-RP mapping algorithm
skipping to change at page 14, line 5 skipping to change at page 14, line 5
group ranges for Dense mode or SSM. group ranges for Dense mode or SSM.
Also all the entries which are already included in the SSM Range Also all the entries which are already included in the SSM Range
table in the IP Mcast MIB would be copied over to table in the IP Mcast MIB would be copied over to
pimGroupMappingTable. They would have a type of configSSM and an RP pimGroupMappingTable. They would have a type of configSSM and an RP
with address type 'unknown' as described above. with address type 'unknown' as described above.
The advantage of keeping all the ranges in the table would be that The advantage of keeping all the ranges in the table would be that
this table will contain all the known multicast group ranges. this table will contain all the known multicast group ranges.
9. Migration to the new algorithm 9. Use of dynamic group-to-rp mapping protocols
The Group-to-RP mapping algorithm proposed in this document obsoletes In practice, it is not usually necessary to run several dynamic
the use of the hash function. With this change, there will be no Group-to-RP mapping mechanisms in one administrative domain.
interoperability between the old and the new algorithm. So networks Specifically, interoperation of BSR and AutoRP is OPTIONAL and not
that use multiple RP addresses for a Group Range and use the hash recommended by this document.
function for load sharing will need to be migrated to the new
algorithm proposed in this document. A seamless migration to the new However, if a router does receive two overlapping sets of Group-to-RP
Group-to-RP algorithm can be accomplished by using one RP address mappings, for example from AutoRP and BSR, then some algorithm is
with Anycast RP. needed to deterministically resolve the situation. The algorithm in
this document MUST be used. This can be important at domain border
routers, and is likely to improve stability under misconfiguration
and when configuration is changing.
An implementation of PIM that supports only one mechanism for
learning Group-to-RP mappings SHOULD also use this algorithm. The
algorithm has been chosen so that existing standard implementations
are already compliant.
10. Security Consideration 10. Security Consideration
This document does not suggest any protocol specific functionality so This document does not suggest any protocol specific functionality so
there is no security related consideration. there is no security related consideration.
11. IANA Consideration 11. IANA Consideration
This draft does not create any namespace for IANA to manage. This draft does not create any namespace for IANA to manage.
 End of changes. 25 change blocks. 
61 lines changed or deleted 81 lines changed or added

This html diff was produced by rfcdiff 1.37a. The latest version is available from http://tools.ietf.org/tools/rfcdiff/